Body structure for motor vehicle

ABSTRACT

A side body structure of a motor vehicle includes a first and second crash boxes at the connecting portion of a side sill and a rear wheel arch. The first crash box is provided outside of a side sill reinforcement and the second crash box is inside the side sill reinforcement. The second crash box is connected with a cross member extended in a transversal direction of the vehicle. In the event of a side impact, first the first crash box collapses and then the second crash box does. Finally, the impact energy is transferred to and absorbed by other body structures through the cross member. The side sill portion and the rear wheel arch portion can be prevented from intruding into a rear compartment so as to save passengers from serious injury.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a body structure of a motor vehicle andparticularly to a side body structure in the vicinity of a rear sidesill and of a rear wheel arch.

2. Prior Art

Generally, in motor vehicles, a rear wheel arch portion (rear wheelhouse) is constituted by a rear wheel arch inner panel and a rear wheelapron connected therewith from inside. Further, the rear wheel archportion is connected at the front end of the wheel arch inner panel withthe rear end of a side sill extended in a lengthwise direction of thevehicle. Further, the rear wheel arch inner panel is connected at aflange portion thereof with a side outer panel. There are severalproposed techniques for raising the strength of the connecting point ofthe front end of the wheel arch inner panel and the rear end of the sidesill. For example, Japanese Utility Model Application No. Jitsu-Kai-Hei1-27992 discloses a side body structure in which a gusset is fixed tothe connecting portion of the front end of the wheel arch inner paneland the rear end of the side panel.

In the event of a side impact, generally, since the vehicle gets damageson the whole side face of the vehicle body, it is necessary that therear side face including the area from the rear part of the side sill tothe rear wheel arch portion also has an effective energy absorptionstructure similar to those of a front pillar and a center pillar.

The side body structure having a gusset at the connecting point of theside sill and the rear wheel arch, as disclosed in the above prior art,is insufficient from the aspect of energy absorption, because in theevent of a side impact the area of the connecting point including thegusset, the side sill portion and the rear wheel arch portion areprotruded into the rear passenger compartment. As a result the passengeris likely to be seriously injured.

SUMMARY OF THE INVENTION

The present invention is intended to obviate the disadvantage of theprior art and it is summarized as follows.

It is an object of the present invention to provide a side bodystructure capable of preventing the side sill portion and the rear wheelarch portion from intruding into a rear passenger compartment in anevent of the side impact.

Further, it is an object of the present invention to provide a side bodystructure by which a side impact energy can be absorbed effectively anddispersed broadly to other body structures.

A side body structure of a motor vehicle according to the presentinvention has a side sill comprising a side sill inner panel, a sidesill outer panel and a side sill reinforcement provided between the sidesill inner panel and the side sill outer panel. The side body structurealso includes a rear floor and a rear wheel arch.

The side body structure according to the first embodiment of the presentinvention includes the following:

a crash box reinforcement that has a U-shaped cross section and locatedoutside of the side sill reinforcement;

a crash box that has a closed cross section formed by the side crash boxreinforcement and by the side sill reinforcement located outside of theside sill reinforcement, and secured to the side sill and to the rearwheel arch so as to connect the side sill and the rear wheel arch; and

a beam member mounted on the rear floor in a transversal direction ofthe vehicle and connected at an outside end thereof with the side silland with the crash box.

Further, the side body structure according to the second embodiment ofthe present invention includes the following:

a first crash box reinforcement with a U-shaped cross section andprovided outside of said side sill reinforcement;

a first crash box having a closed cross section formed by the firstcrash box reinforcement and by the side sill reinforcement, and securedto the side sill and to the rear wheel arch so as to connect the sidesill and the rear wheel arch;

a second crash box reinforcement having a U-shaped cross section andlocated inside the side sill reinforcement;

a second crash box having a closed cross section formed by the secondcrash box reinforcement and by the side sill reinforcement, and locatedon the opposite side of the first crash box with respect to the sidesill reinforcement, and connected with the rear floor.

Furthermore, the side body structure according to the third embodimentof the present invention includes in addition to the second aspect:

a beam member provided on the rear floor in a transversal direction ofthe vehicle and connected at an outside end thereof with the side silland with the second crash box.

BRIEF DESCRIPTION OF THE DRAWINGS

A specific embodiment according to the present invention will bedescribed with reference to the accompanying drawings, in which:

FIG. 1a is a perspective view from inside of a vehicle of a firstembodiment showing a connecting portion of a side sill and a rear wheel;

FIG. 1b is a perspective view from outside of a vehicle of the firstembodiment showing a connecting portion of a side sill and a rear wheelarch;

FIG. 1c is a cross sectional view of a C--C section in FIG. 1b.

FIG. 2a is a perspective view from inside of a vehicle of the secondembodiment showing a connecting portion of a side sill and a rear wheelarch;

FIG. 2b is a cross sectional view of a B--B section in FIG. 2a;

FIG. 3a is a perspective view from inside of a vehicle of the thirdembodiment showing a connecting portion of a side sill and rear wheelarch;

FIG. 3b is a cross sectional view of a B--B section in FIG. 3a; and

FIG. 4 is a perspective view from inside of a vehicle of the thirdembodiment showing a beam member and others.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments according to the present invention will be described indetail by referring to the accompanying drawings.

Referring now to FIG. 1, this shows a first embodiment according to thepresent invention, A side sill having a closed cross section so that itis extended in a lengthwise direction of a vehicle. The side sill, as isknown, is constituted by a side sill inner panel 11, a side sill outerpanel 12, and a side sill reinforcement 13. Further, numeral 2 denotes arear wheel arch which is constituted by a rear wheel apron 21 and a rearwheel arch inner panel 22 secured at an inner flange portion thereof toa rear end of the rear wheel apron 21. The outside of the rear wheelarch inner panel 22 is covered by a side outer panel 3 and the front endthereof is secured to the rear end of the side sill 1.

Further, the left and right side flange portions of a front floor 40 aresecured to the inner face of the left and rear side sills 1. In the samemanner, the left and right side flange portions of a rear floor 4 aresecured to the rear inner face of the left and right rear side sills 1and to the rear inner face of the rear wheel apron 21.

Numeral 5 denotes a reinforcement having an approximate U-shaped crosssection in its fundamental configuration. The reinforcement 5, asillustrated in FIG. 1b, is secured at the front portion thereof to theoutside face of a side sill reinforcement 13 and at the rear portionthereof to the rear wheel arch inner panel 22. In this construction, acrash box 6 having a closed cross section constituted by the side sillreinforcement 13 and the reinforcement 5 is formed so as to connect therear portion of the side sill 1 with the rear wheel arch 2. As shown inFIG. 1c, the outside of the crash box 6 is covered by the side sillouter panel 12 and the side outer panel 3 and the inside thereof isprotruded upwards of the side sill inner panel 11 and the rear wheelarch inner panel 22 at the connecting point of the side sill 1 and therear wheel arch 2.

Further, as shown in FIG. 1c, the above protruding portion of the crashbox 6 is secured by butt-welding on the inside face thereof to an outerend of a rear arch beam member 7 extended in the transversal directionof the vehicle. The rear arch beam member 7 is connected by butt-weldingat the left and right outside ends thereof with the side sill innerpanel 11, the rear wheel arch inner panel 22 and the rear wheel apron 21respectively. As shown in FIG. 1c, the left and right crash box 6, theleft and right side sill 1, and the rear arch beam member 7 areconnected with each other and form a closed cross sectional structure.The rear arch beam member 7 is constituted such that it is low and thinat the middle portion thereof and becomes gradually higher and widertowards the left and right outside end portion thereof. Further, numeral8 denotes a rear side flange extended in a lengthwise direction of thevehicle.

As described above, since the body structure according to the firstembodiment is constructed such that the connecting portion of the sidesill 1 and the rear wheel arch 2 is reinforced by the crash box 6 andfurther the crash box 6 is firmly held by the rear arch beam member 7,the rear portion of the side sill I and the rear wheel arch 2 can beprevented from intruding into the rear compartment in the case where thevehicle has a side impact. Namely, first the impact energy is absorbedby the deformation and collapse of the crash box 6 and then it istransferred and dispersed broadly to the crash box 6 on the other sideand to the rear floor 4 through the rear arch beam member 7.

Further, in this construction, by means of the closed cross sectionformed by the side sill outer panel 12 and the side sill reinforcement13 and the crash box 6 connected with this closed cross section, therear wheel arch 2 can have an effective energy absorption capabilitysimilar to those of the center pillar and the front pillar. This is areasonable body structure fit for small vehicles whose space is limited.

Referring to FIGS. 2a and 2b for showing the second embodiment of thepresent invention, in this example an inner crash box 6' is provided atthe inner side of the crash box 6 in place of the rear arch beam member7. The inner crash box 6' has a closed cross section formed by anextended portion of the side sill inner panel 11 and the side sillreinforcement 13. Other structures are the same as those in the firstembodiment.

In this second embodiment, in the event of the side impact, since theinner crash box 6' firmly holds the crash box 6 from the inside, theimpact energy is absorbed by the collapse of the crash box 6 and then bythe collapse of the inner crash box 6'. As a result, the intrusion speedof the rear door into the rear compartment is restricted and the impactload is broadly dispersed to the rear floor 4, the rear wheel apron 21and other members. Further, since there is not a large structural memberas the rear arch beam member, a further compact energy absorbingstructure can be achieved.

FIGS. 3a and 3b indicate an example according to the third embodiment.In this third embodiment, the inner crash box 6' is provided in additionto the crash box 6 described in the second embodiment. Further, a crossmember 9 is secured to the rising face 4a of a seat riser from the frontfloor 40 such that it forms a closed cross section in the transversaldirection of the vehicle. In this embodiment, a rear arch holder 9aintegrally formed with the cross member 9 at the left and right endsthereof is connected by welding to the inside face of the inner crashbox 6' in such a way that it expands backward and upward and enclosesthe whole inner crash box 6' from inside.

As described above, in the third embodiment, since the inner crash box6' supports the crash box 6 from the inside and further the cross member9 holds the inner cross member 6' from inside through the rear archholder 9a, the impact energy is received more firmly.

FIG. 4 indicates another example of the third embodiment in which a reararch beam member 7' having a U-shaped cross section is secured on therear floor 4. The rear arch beam member 7' is integrally formed with theaforementioned cross member 9, that is, in this embodiment, the crossmember 9 comprises a front closed section "a" with a large sectionalarea and a rear closed cross section "b" with a small sectional area.Both or either of these cross members are secured to the inside face ofthe inner crush box 6'.

Further, as a variation of the first embodiment shown in FIG. 1a,substituting for the rear arch beam member 7, the rear arch holder 9a orthe rear arch cross member 7' may be constituted so as to support thecrash box 6 from inside.

Further, as a further variation of the first embodiment, the rear archbeam member 7 may be provided so as to support the inner crash box 6'from inside.

In summary, the present invention is characterized by the crash boxconnecting to the side sill and the rear wheel arch. Further, in thesecond embodiment, the inner crash box is provided in addition to theabove crash box on the inside face of the crash box. When the sideimpact is applied to the rear side face of the vehicle, the side sillportion and the rear wheel arch portion are prevented from intrudinginto the rear compartment by the energy absorption of these crash boxes.

While the presently preferred embodiments of the present invention havebeen shown and described, it is to be understood that these disclosuresare for the purpose of illustration and that various changes andmodifications may be made without departing from the scope of theinvention as set forth in the appended claims.

What is claimed is:
 1. A body structure of a motor vehicle having a side sill including a side sill inner panel, a side sill outer panel and a side sill reinforcement provided between said side sill inner panel and said side sill outer panel, a rear floor and a rear wheel arch, comprising:a crash box reinforcement including a U-shaped cross section and provided outside of said side sill reinforcement; a crash box including a closed cross section formed by said side crash box reinforcement and by said side sill reinforcement and provided outside of said side sill reinforcement and secured to said side sill and to said rear wheel arch so as to connect said side sill and said rear wheel arch; and a cross member provided on said rear floor in a transversal direction of said vehicle and connected at an outside end thereof with said side sill and with said crash box.
 2. The body structure according to claim 1, whereinsaid cross member has a closed cross section formed by at least one U-shaped channel and said rear floor and is formed such that it is relatively low in height at the middle portion thereof and is relatively high in height and relatively broad in width at the outside end thereof. 